On 8/22/26 02:11, syzbot wrote: > Hello, > > syzbot found the following issue on: > > HEAD commit: 8d3ae59288f1 Linux 7.2 > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=10240679580000 > kernel config: https://syzkaller.appspot.com/x/.config?x=4c9eb8e593cf8c5c > dashboard link: https://syzkaller.appspot.com/bug?extid=13df72e0dc4be5c62215 > compiler: Debian clang version 22.1.8 > (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8 >
virtio-balloon in an RT kernel/environment, unlikely in pactice ... :) > Unfortunately, I don't have any reproducer for this issue yet. > > Downloadable assets: > disk image: > https://storage.googleapis.com/syzbot-assets/cd49b631c498/disk-8d3ae592.raw.xz > vmlinux: > https://storage.googleapis.com/syzbot-assets/05d3ad83c130/vmlinux-8d3ae592.xz > kernel image: > https://storage.googleapis.com/syzbot-assets/3a2efa4a6769/bzImage-8d3ae592.xz > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: [email protected] > > INFO: trying to register non-static key. > The code is fine but needs lockdep annotation, or maybe > you didn't initialize this object before use? > turning off the locking correctness validator. > CPU: 0 UID: 0 PID: 20235 Comm: irq/10-virtio2 Tainted: G L > syzkaller #0 PREEMPT_{RT,(full)} > Tainted: [L]=SOFTLOCKUP > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > Google 07/24/2026 > Call Trace: > <TASK> > dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 > assign_lock_key+0x133/0x150 kernel/locking/lockdep.c:984 > register_lock_class+0xcc/0x2e0 kernel/locking/lockdep.c:1299 > __lock_acquire+0xab/0x2ce0 kernel/locking/lockdep.c:5112 > lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868 > rt_spin_lock+0x83/0x400 kernel/locking/spinlock_rt.c:56 > spin_lock include/linux/spinlock_rt.h:45 [inline] > start_wakeup_event drivers/virtio/virtio_balloon.c:150 [inline] > stats_request+0xa5/0x1f0 drivers/virtio/virtio_balloon.c:435 I don't really understand what's happening here, Is the register_lock_class() trying to reguster a non-static key? I don't immediately see how virtio-balloon is doing something odd here, all it does is a spin_lock_irqsave(&vb->wakeup_lock, flags), that was earlier initialized with spin_lock_init(&vb->wakeup_lock), before the device was ready. -- Cheers, David
